Multi-symbol signals including an initial symbol and an extension portion

Abstract

A base station generates and transmits a multi-symbol beacon/timing synchronization signal. The multi-symbol beacon/timing synchronization signal includes: (i) an initial symbol including a body portion and a cyclic prefix, the cyclic prefix preceding the body portion and being generated from an end portion of the body portion and (ii) an extension symbol, which immediately follows the initial symbol. The extension symbol includes a first copy of the body portion beginning at the start of the extension symbol. The first copy of the body portion is immediately followed by a truncated portion, which is a copy of an initial portion of the body portion. The multi-symbol beacon/timing synchronization signal includes a single high power beacon tone, a plurality of low power tones comprising the synchronization signal, and a plurality of intentional Null tones. Each tone designation remains the same for both the initial symbol and the extension symbol.

1 . A method of operating a base station transmitter comprising: 
 generating a multi-symbol signal including: 
 generating an initial symbol including a cyclic prefix portion and a body portion, said body portion immediately following said cyclic prefix portion;  
 generating an symbol extension portion that immediately follows said initial symbol in said multi-symbol signal, said symbol extension including a first copy of said body portion beginning from the start of said symbol extension portion; and  
 transmitting said generated multi-symbol signal.  
   
     
     
         2 . The method of  claim 1 , wherein generating an initial symbol including a cyclic prefix portion includes copy an end portion of said body portion to be used as said cyclic prefix.  
     
     
         3 . The method of  claim 2 , wherein said multi-symbol signal is an OFDM signal.  
     
     
         4 . The method of  claim 3 , wherein said extension portion has a duration of at least one OFDM symbol time period and includes at least a first extension symbol.  
     
     
         5 . The method of  claim 4 , further comprising: 
 including a truncated portion of said body portion in said first extension symbol, said truncated portion including an initial portion of said body portion, said truncated portion of said extension symbol immediately following said first copy of said body portion.    
     
     
         6 . The method of  claim 3 , wherein said initial symbol and said extension portion each include a single tone used in both said initial symbol and said extension portion to carry a beacon signal, said transmitter placing more energy on said single tone than any other tone in said initial symbol.  
     
     
         7 . The method of  claim 6 , wherein the per tone energy placed on said single tone is at least 6 db higher than any other tone included in said initial symbol.  
     
     
         8 . The method of  claim 6 , wherein the body portion of the initial symbol and the extend symbol each include multiple tones, the method further comprising: 
 including a plurality of tones corresponding to a synchronization signal in both the body portion of said initial symbol and said extension portion, said plurality of tones used for said synchronization signal being the same in both said initial symbol and said extension portion.    
     
     
         9 . The method of  claim 8 , further including a plurality of NULL tones in both said initial symbol and said extension portion, said plurality of NULL tones used for said synchronization signal being the same in both said initial symbol and said extension portion.  
     
     
         10 . The method of  claim 6 , wherein said initial OFDM symbol includes the full set of downlink tones transmitted by said base station during the period of said initial OFDM symbol.  
     
     
         11 . The method of  claim 10 , wherein said full set of downlink tones includes one of 113 and 339 tones.  
     
     
         12 . The method of  claim 3 , further comprising: 
 generating a first OFDM user data symbol, said step of generating said first OFDM user data symbol including: 
 i) generating a first user data body portion including at least some user data;  
 ii) generating a first user data cyclic prefix which is a copy of a portion of said first user data body portion, said user data body portion immediately following said user data cyclic prefix portion in said first user data symbol; and  
   transmitting said first user data symbol.    
     
     
         13 . The method of  claim 12 , further comprising: 
 generating a second OFDM user data symbol, said step of generating said second OFDM user data symbol including: 
 i) generating a second user data body portion including at least some additional user data;  
 ii) generating a second user data cyclic prefix which is a copy of a portion of said second user data body portion, said second user data body portion immediately following said second user data cyclic prefix portion in said second user data symbol; and  
   transmitting said second user data symbol.    
     
     
         14 . The method of  claim 13 , wherein each tone of the first and second user data symbols are transmitted at a per tone power level which is at least 6 dB lower than the highest per tone power level of a tone in said initial symbol.  
     
     
         15 . A base station comprising: 
 a signal generator for generating a multi-symbol signal, said signal generator including: 
 an initial symbol generation module for generating an initial symbol including a cyclic prefix portion and a body portion, said body portion immediately following said cyclic prefix portion;  
 a symbol extension generation module for generating a symbol extension portion that immediately follows said initial symbol in said multi-symbol signal, said symbol extension including a first copy of said body portion beginning from the start of said symbol extension portion; and  
 a transmitter coupled to said signal generator module for transmitting said generated multi-symbol signal as a plurality of consecutive symbols.  
   
     
     
         16 . The base station of  claim 15 , wherein said initial symbol generation module include a cyclic prefix generation module for generating the cyclic prefix portion by copying an end portion of said body portion.  
     
     
         17 . The base station of  claim 16 , wherein said transmitter is an OFDM signal transmitter.  
     
     
         18 . The base station of  claim 17 , wherein said extension portion has a duration of at least one OFDM symbol time period and includes at least a first extension symbol.  
     
     
         19 . The base station of  claim 18 , further comprising: 
 a truncation module for including a truncated portion of said body portion in said first extension symbol, said truncated portion including an initial portion of said body portion, said truncated portion of said extension symbol immediately following said first copy of said body portion.    
     
     
         20 . The base station of  claim 17 , wherein said initial symbol and said extension portion each include a single tone used in both said initial symbol and said extension portion to carry a beacon signal, said base station further comprising: a power scaling module for placing more energy on said single tone than any other tone in said initial symbol.  
     
     
         21 . The base station of  claim 20 , wherein the per tone energy placed on said single tone is at least 6 db higher than any other tone included in said initial symbol.  
     
     
         22 . The base station of  claim 20 , wherein the body portion of the initial symbol and the extension symbol each include multiple tones, the base station further comprising: 
 a synchronization signal generator module for including a plurality of tones corresponding to a synchronization signal in both the body portion of said initial symbol and said extension portion, said plurality of tones used for said synchronization signal being the same in both said initial symbol and said extension portion.    
     
     
         23 . The base station of  claim 22 , further including a NULL tone assignment module for control said transmitter not to place energy on a plurality of NULL tones in both said initial symbol and said extension portion, said plurality of NULL tones used for said multi-symbol signal being the same in both said initial symbol and said extension portion.  
     
     
         24 . The base station of  claim 21 , wherein said initial OFDM symbol includes a full set of downlink tones transmitted by said base station during the period of said initial OFDM symbol.  
     
     
         25 . The base station of  claim 24 , wherein said transmitter uses said full set of downlink tones, said full set of downlink tones including one of 113 and 339 tones.  
     
     
         26 . The base station of  claim 25 , wherein each tone of said full set of tones is one of a beacon tone, a synchronization signal tone, and a NULL tone during said multi-symbol signal.